While leaning out a window that is 5.70 m above the ground, you drop a 0.600-kg basketball to a friend at ground level. your friend catches the ball at a height of 2.00 m above the ground. determine the following.
(a) the amount of work done by the force of gravity on the ball
(b) the gravitational potential energy of the ball-earth system, relative to the ground when it is released
(c) the gravitational potential energy of the ball-earth system, relative to the ground when it is caught
(d) the ratio of the change (pef − pe0) in the gravitational potential energy of the ball-earth system to the work done on the ball by the force of gravity

a)21.756 J

b)33.516 J

c)11.52 J

d)-1

Explanation:

Net fall in height of ball= 5.70-2.0= 3.70 m

a)  work done by the force of gravity on the ball = Mg*h = 0.6×9.8×3.7 = 21.756 J

b) gravitational potential energy of the ball-earth system, relative to the ground when it is released = 0.6×9.8×5.70 = 33.516 J (ans)

c) the gravitational potential energy of the ball-earth system, relative to the ground when it is caught = 0.6×9.8×2 = 11.52 J

d) ratio of the change (PE_f − PE_0) in the gravitational potential energy of the ball-earth system to the work done on the ball by the force of gravity = (11.52 -33.51)/(21.756) ≅-1 (ans)

b) phosphorus pentoxide

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